This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. How do brown capuchin monkeys (Cebus apella) react to their group mates in terms of the knowledge they have and prosocial vs. competitive tendencies? In the last year we published several papers (first author: Pokorny) on face recognition, since we found that capuchin monkeys have a very acute recognition, and are able to tell group mates from non group mates from portraits alone, which is the first such evidence for monkeys. We also found evidence for cooperation and prosocial choice, especially the increase of such choice under conditions that allow reciprocity These projects are currently being written up (Suchak as first author). Another recent projects concerns cultural learning (i.e. how monkeys learn from each other and how habits spread in a group), which have been quite successful (first author: Dindo). Available are 30 capuchin monkeys, kept in indoor/outdoor enclosures, trained for temporary separation for experiments. Our studies illuminate basic social cognition that is often taken for granted. The laboratory at the Yerkes primate Center serves the education of a great many undergraduate and graduate students, who obtain valuable training in combination with classes they take. Through his popular books and lectures, the Principal Investigator is at the forefront in communicating findings in animal behavior to a wider public, both academic and nonacademic.